1. Field of the Invention
This invention relates to a rotatable windmill blade assembly that is rotated in response to the wind. The rotatable windmill blade assembly is connected by means of a correspondingly rotatable shaft to, for example, an electrical power generator.
2. Background Art
Clean, efficient and low-cost sources of energy are regularly being sought by individuals and government agencies alike. By way of example, attempts have been made to harness the wind to produce electricity to power individual households or communities. To this end, arrays of tall windmills have been erected in out-of-doors areas where regular air currents are prevalent. The windmills have rotatable propellers that spin in response to the wind. Each windmill functions as a turbine, whereby a rotation of the propeller thereof results in the generation of electricity.
The efficiency of the windmill and the power output of the turbine are dictated to a large extent by the size and pitch of the blades of the rotatable propeller. The blades of the propeller typically project outwardly from a common hub such that all of the blades are coplanar. It would be desirable to vary the pitch of the blades of a rotatable windmill blade assembly to optimize the aerodynamic characteristics thereof in order to maximize the responsiveness of the blades to wind flow, whereby the blade assembly can spin at higher speeds so that the turbine can correspondingly generate electricity more efficiently.